Resistive-switching nonvolatile random access memory (RRAM) has attracted wide attention and been developed because of numerous advantages including its simple cell structure, low operational voltage, fast switching speed and high integration density.
Usually, RRAM is made in metal-insulator-mental (MIM) configuration, which is simple but can be made by backend manufacturing process only, and cannot be integrated to the frontend process, which increases the manufacturing cost.
Recently, HfO2-based gate dielectrics and Ni gate electrodes are used to form capacitors in a metal-insulator-silicon (MIS) configuration, which was found to have the characteristic of the resistive switching. Ergo, based on the characteristic, the present invention proposes a multi-bit resistive-switching random access memory cell and the detail follows.